/Engine/Source/Runtime/Engine/Classes/Animation/AnimInstance.h
Play normal animation asset on the slot node by creating a dynamicUAnimMontagewith blend in settings. You can only play one asset (whether montage or animsequence) at a time per SlotGroup.
[UAnimMontage](API\Runtime\Engine\Animation\UAnimMontage) * PlaySlotAnimationAsDynamicMontage_WithBlendSettings ( [UAnimSequenceBase](API\Runtime\Engine\Animation\UAnimSequenceBase) * Asset, [FName](API\Runtime\Core\UObject\FName) SlotNodeName, const [FMontageBlendSettings](API\Runtime\Engine\Animation\FMontageBlendSettings) & BlendInSettings, const [FMontageBlendSettings](API\Runtime\Engine\Animation\FMontageBlendSettings) & BlendOutSettings, float InPlayRate, int32 LoopCount, float BlendOutTriggerTime, float InTimeToStartMontageAt )